Limits Testing for Salmonella What a Difference A Year Makes Part 2

Posted by Lisa Leier-McHugh on Mar 23, 2016 9:10:52 AM

Discovering New Applications for Poultry Limits Testing


Roka has worked on several applications using the Limits based approach in situations from live production environments to pre and post chill rinsates, as well as parts, trim and ground fresh products. Each situation and matrix reveal new information to a company which is valuable and useful for their particular situation.  

The concept with limits testing is more about detecting the load or concentration of the pathogen within a specific type of sample. This gives processors an opportunity to actually manage the levels of pathogen across the poultry production chain. Here are a few examples where limits testing is being used in both upstream and downstream processes. When applied to live production, limits testing allows for the identification of potential “hot” flocks and grow houses prior to processing. For the parts rinses application, it allows processors to define and eliminate hot flocks from entering the grinding process. And when applied to final ground product, it allows for the rapid identification of higher load outlier product to make diversion decisions.

Considerations with Limits Testing

A word of caution when considering technologies and design. As with any new approach to an existing problem, technologies everywhere may be quick to jump on a bandwagon. It is important to note that data and study over the past 2 plus years in partnership with multiple stake holders who have now converted into commercial application is what is behind one of the most promising tools available in the “War on Salmonella”. That data is also available to be shared in support of others desiring to incorporate this rapid approach to existing Salmonella testing programs.

Why the Atlas System?

As far as buzz around some circles during IPPE 2016, I was asked repeatedly, “Why can’t any testing technology do this sort of testing?”  The answer really is a series of varied strengths and capabilities that the Atlas System has. The combination of Target Capture, TMA of the RNA target and Hybridization Protection Assay give the test 3 levels of specificity. Because the novel clean-up step of Target Capture technology allows artifact, competing nucleic acids and other bacterial or chemical inhibitions to be removed prior to amplification, the poultry industry can now look at samples previously considered “off limits” for examination and without extreme and expensive manipulation to find the target. In addition, using an RNA-based target allows a sensitivity up to 2 logs higher than other nucleic acid based assays, even in the most challenging of matrices. This unique combination of molecular technologies is what attributes to the Atlas® Salmonella detection assay’s superior specificity, accuracy and sensitivity in comparison to other methods currently on the market. This is why a Limits based test can be completed between 4-8 hours (sample received to result).

I have worked in the food safety testing industry since 2001 and have worked with several methods for the detection of Salmonella (plates to PCR and much in between). Without a doubt the engineering and design of the assay in combination with instrument platform, make it a solid yet flexible Salmonella assay. As hurdles and intervention continue to push further and further back into production, this ability to accurately detect semi-quantitative concentrations of Salmonella becomes more crucial. The applications flexibility, along with its unique and robust nature the technology truly represents a breakthrough for the detection and management of Salmonella.

What a difference a year can make, from “Buzz” word, to a validated implemented approach. Limits testing using the Atlas System by Roka Bioscience has moved from buzz word to quickly becoming a mainstay in our food safety vernacular.

Please feel free to reach out to me at if you would be interested in learning more about limits and the data surrounding it.

For more information on this topic view a presentation done at a major poultry industry event t

Limits Testing Applications from Live Production to Finished Product An Additional Lens for Salmonella Load and Process Control 
Download and View Limits   Testing Presentation 




Topics: Limits Testing